Apparatus for synchronizing the speeds of power-driven mechanisms



Feb. l-O, 1953 E. M. MAY

APPARATUS FOR sYNcHRoNIzING THE sPEEDs 0F POWER-DRIVEN'MECHANISMS Original Filed Dec. 30, 1946 3 Sheets-Sheet l Feb. l0, 1953 E. M. MAE '2,627,762

APPARATUS FOR sYNcHRONl 4vNG THE sPEEDs 0F POWER-DRIVEN MECHANISMS Original Filed D60. 30, 1946 3 Sheets-Sheet 3 IN VEN TOR.

ATTORNEYS Patented Feb. 10, 1953 APPARATUS FOR SYNCHRONIZING THE SPEEDS OF POWER-DRIVEN MECHA- NISMS Edward M. May, Detroit, Mich., assignor to Meco- Pilot Manufacturing Company, Detroit, Mich., a corporation of Michigan Original application December 30, 1946, Serial No. 719,305. Divided and this application October 3, 1951, Serial N0. 249,483

1 Claim. 1

The invention relates to means for synchronizing the speeds of two power-driven mechanisms driven by separate motors. The present application is a division of my earlier application Serial No. 719,305, iiled December 30, 1946, the motor-driven mechanisms synchronized in accordance with the present invention being a pair of the motor-driven hydraulic control mechanisms of the character disclosed in the earlier application.

It is an object of the present invention to provide a pair of the motor driven control mechanisms having hydraulic coordinating means causing the two mechanisms to operate synchronously at relative speeds which are subject to predetermination by adjustment of the apparatus.

For the attainment of the above-stated object and others of an incidental or ancillary nature the invention consists in the forms, arrangements and combinations of parts defined in the appended claim and explained in the following description of an exemplary apparatus shown in the accompanying drawings.

In the drawings,

Fig. l is a front elevation oi a unitary control apparatus of which a plurality can be operatively combined in carrying out the present invention.

Fig. 2 is a right side elevation oi the apparatus shown in Fig. 1 with a portion of the casing structure broken away to show interior parts and with hinged cover portions of the casing structure shown in closed position by iull lines and in open position by dashed lines.

Fig. 3 is a View partially diagrammatic, showing the cam and hydraulic transmitter devices of the control unit in plan view on a larger scale than in Figs. l and 2 with some parts omitted and others shown in section, and also showing one of the hydraulically actuated elements of a turret lathe to be controlled and motor-driven pump means for supplying power liquid for the hydraulic motor of the lathe, subject to pressure control of the power liquid by the cam apparatus.

Fig. 4 is an enlarged sectional view on the broken line 4-4 of Fig. 3 with some parts of the structure broken away.

Fig. 5 is a diagrammatic view showing an operative interconnection of two hydraulic control mechanisms of the character shown in the other views constructed to secure synchronous drive of the two mechanisms.

Referring in detail to the constructions illustrated and rst to the single control mechanism shown in Figs. 1 4, numeral I designates as an entirety (Figs. 1 and 2) a cabinet designed to rest upon the oor and house a hydraulic transmitter apparatus in accordance with the invention. The cabinet is preferably built up of sheet steel and is tted with a pair of bottom skids 2, 2 adapted to slide upon the floor when the apparatus is moved. The front of the cabinet may be left open as shown but the top is partially closed by cover sections 3 and 4 which are hinged on the body of the cabinet at 3a and 4a, respectively, so that they can be swung downward to the positions shown in dotted lines to give free access to the apparatus within the cabinet and at the same time serve as shelves for tools and parts when changes and adjustments of the apparatus are being made. The rear cover 4 is disposed at a higher level than the front cover 3 so that an inspection opening or window is provided at 5 for a purpose which will presently appear. The cover 4 is formed in its top portion with an opening 4b over which are arranged an electric light bulb 6, preferably of the elongated tubular type, and a reflector l, the purpose of the light being to illuminate parts of the enclosed apparatus as viewed through opening 5.

Within the upper part of the cabinet I is a rectangular frame 8 secured to the walls of the cabinet by bolts or screws (not shown), the said frame being inclined downwardly from the rear to the front of the cabinet as shown in Fig. 2. As best shown in Fig. 3, the rear side of frame 8 carries a series of hydraulic transmitters 9, 9 two of which have been omitted to facilitate disclosure of other parts. Each transmitter comprises a block I0 formed at its front end with a transverse cylinder chamber II (Fig. 4). This chamber is closed at its respective ends by heads l2 and I3. Within chamber II is a piston structure I4 comprising a disc I5, hydraulic packing IB and retaining ring I'I. The piston is fast on a rod I8 which is guided at one end in a boss carried by the head I2 and at its other end extends through an aperture in the head I 3 ntted with a suitable hydraulic packing I9. The cylinder block I0 is formed on its top side with a threaded aperture 20 to which is connected a conduit 2| designed to connect chamber II with receiver apparatus which will later be described. The cylinder block I0 of each transmitter is also formed with a top recess to receive an upright, open-topped tubular reservoir 22 of transparent material such as plastic or glass. The reservoir is designed to hold oil or other working liquid for the transmitter and has its joint with block I0 packed to prevent leakage. Passages 23 3 and 2 lead from the bottom of the reservoir 22 into the cylinder chamber II, the passage 2li packing I of the piston structure serves to closel the passage 23 as the piston moves forward on its working stroke. A coil spring 25 is interposed between the piston I4 and the head I2 and is adapted to retract the piston following its working stroke. A

To effect the working stroke of the piston I 4 cam devices are provided comprising a horizontal cylinder 23 having a cylindrical shell 2 and end discs 28, 28 which are centrally apertured and secured by set screws or the like on a supporting shaft 29. Shaft 29 in turn is supported by antifriction bearings 3U in the respective ends of frame 3. To permit easj7 removal of the cylinder structure as a unit the end sections of frame 8 are tted with swinging bearing caps 3| which are hinged at their front ends to the frame and are disengageably secured at their rear ends by swinging bolts 32.

The cylinder 26 is formed peripherally to receive a series of circumferentially extending cams 33, 33, one for each of the transmitters 9, 9. That is to say, the cylinder has a series of circumferentially extending cam seats Zia extending radially somewhat beyond the main surface of the shell 27, and adjacent each seat surface 21a the shell is formed with a circumferentially extending shoulder 2lb to Yengage and locate one of the cams, each of which has a straight longitudinal edge affording a reference surface to cooperate with the locating shoulder 2lb. Each cam 33 is preferably formed from an elongated relatively thin strip of metal or other material susceptible of being manually bent from the flat state to circular form and preferably also possessing sucient elasticity to return substantially to the flat state when released. Aluminum alloy sheet material of suitable temper is a satisfactory material for the purpose.

Each of the cams 33 is provided adjacent its two ends with apertures to receive securing screws 34,

34 which engage threaded holes Z'Ic, 21e of the cylinder drum 27, and is also provided adjacent one end with a dowel hole to engage a dowel piny 35 attached to drum shell 27. Each cam may if desired be provided with additional securing screws spaced around the periphery of the cam drum. As will be apparent from Fig. 3, each of the cams 33 has one longitudinal edge formedof the piston rod I5. The pivotal support for the arm 35 is aorded by pin 36 carried by the head of a bolt 39 having a swiveling support in the rear part of receiver block Iii. With this construction the follower arm 36 can be raised Vwhen desired as indicated by dotted lines in Fig. 2 to permit removal of the cam cylinder 26 from frame 8. The swiveling bolt 39 is tted with 'a washer 39a. and

` a coil spring l which engages the bclt washer Aand yieldingly presses the head of the bolt against the adjacent face of block l (Fig. 3). To support the roller 3l in operative engagement with the edge of the cam 33 the side of follower arm 33V v end of each rotation of the drum 25.

( vmeans comprise a lever arm -51 tted at its -f-ront 59h. able to stop the control mechanism at 4the rend vof each cycle and have the apparatus started where it engages the piston rod I8 is formed with an angular groove or depression 33a as shown in Fig, 4. The engagement between the arm and the end of the rod is normally maintained by the tension of the spring 25. As is shown in Fig. 4 the follower arm 36 during normal operation lies within a slot i3d of the cylinder head I3.

For reasons later explained it is desirable to be able to adjust the transmitter blocks I0 in relation tc the supporting frame 8 and to this end each block is secured to the frame by a pivot pin 4I (Fig. 4) and a clamping screw i2 which passes through a hole in the block I0 somewhat larger than the shank cf the screw so that the block can be adjusted around the axis of pin 4I.

Rotation of the cam drum is effected by an electric motor 43 which is connected to drive a variable speed mechanism 44 which in turn is connected through worm and wheel gears to drive a pinion 43 meshing with a spur gear 41 fast on shaft 29 of the cam drum. Preferably the motor, variable speed mechanism and worm and wheel gears constitute a unitary device which is supported on the end of cabinet l by a suitable bracket 28. With the described gear connection between the motor and the cam drum the removal of the latter from its supporting frame involves merely the disengagement of the bearing caps 3l and separation of spur gear 41 from the driving pinion 45. For control of motor i3 it is connected in circuit with switch and relay devices 49 and 49', respectively, of well known construction, the switch having a starting button 49a and a stop button 59h. Further reference will be made to these manual control devices later in the description.

The apparatus is further provided with safety devices comprising an emergency switch 50 which is connected in circuit with motor 43. Switch 5I] is normally held in its closed position by means of a double-ended dog 5I xedly secured to a rod 52 which is slidably mounted in bracket 53 and 54 attached to the frame S (Fig. 3). Dogs 55, 55 are adjustably clamped on rod 52, each a little to the right of the head of one of the pivot bolts 39. A coil spring 55 which is interposed between one of the dogs 55 and bracket 5d urges rod r52 toward the left. Rotation of the rod 52 is prevented by the disposition of the arms of dog 5I adjacent the horizontal surface of the bracket 53. With this arrangement if the discharge of any one of the transmitters should be blockaded or movement of the cam follower be in any way obstructed the spring of the pivot bolt will yield and permit the follower arm 33 to swing about the end of piston rod I8 as a pivot with resultant movement of the sliding rod 52 toward the right and the opening of emergency switch 5D.

With the hydraulic transmitters actuated ,by the circular or endless form of cams it isapparent that a cycle of transmitter movements is effected for each rotation of the cam drum 26. `For the control of some types of machines and operations it may be desirable for the control mechanism, when started manually by switch button 59a, to run continuously for the performance of a considerable number of control cycles and then be stopped by manual switch button In other cases, however, it may be desiragain manually. To this latter end means are provided to open emergency switch 50 at the Said end with an antiiriction roller arranged to be engaged by a radial pin 59 carried by cylinder 2t. At its rear end the arm l is slotted to receive the end of eye bolt il@ to which the arm is pivotally connected by pin i. Bolt has a swiveling support in block 62 carried by frame and is fitted at one end with a washer @t which is engaged by spring tl to hold the arm 5i yieldingly against the side surface oi block iii. The rear end of arm 51 is engaged by the front end of clog 5| on the sliding rod 5a and normally serves as a positive stop limiting movement or" rod 52 by spring 56. With this construction when the control apparatus is started by actuation oi the starting switch @sa the cam drum rotates, in the direction or arrow R, until pin engages roller 53 to swing the arm 5l around the right front corner of block as a pivot with resultant movement of the rear end of arm 5l' to the right. This movement carries dog 5l to the right and opens emergency switch 5t to stop the drive motor d3.

In order to insure the proper positioning of roller 5t in relation to the pin or dog 5S, block 62 is adjustably secured to frame 8 by means of pin 65 and clamping screw the clamping screw having a sufficiently loose fit in the block to permit the relatively small range of needed adjustment. When multiple cycle operation without manual control is desired it is only necessary to block up arm El to remove roller 53 from the path of dog such positioning of arm 5l being permitted by the swivel mounting oi bolt 60.

An additional motor control switch lili is mounted on. bracket 53 with its actuating arm disposed adjacent the rear end oi arm 5l. The switch which is normally open, is closed by the above described swinging movement of arin 5l. The purpose of switch il? will appear at a later point in the description.

it is desirable that the stopping of the cam mechanism be eected without any considerable overrun when the control switch is actuated. To this end the motor E is preferably equipped with a magnetic brake so that it will stop promptly when deenergized. Alternatively (and at less cost) use may be made of well known switch and relay circuit means adapted to give the desided quick stopping.

The invention contemplates automatic control of the variable speed mechanism id through which motor d3 is connected to drive the cam drum 2d. To this end gearing ld is provided with a crank arm ddd connected to actuate the speed varying means or" the mechanism. As has been stated any suitable form of speed varying mechanism can be employed but that manufactured by Graham Transmissions Inc., of Milwaukee, Wisconsin, and shown in U. S. Patent No. 2,405,957, has been found satisfactory for use. Crank arm 44a is actuated by a hydraulic receiver comprising cylinder 28 and piston di? having a rod lil with a pin and slot connection to arm lilla. One end of cylinder 8 is connected by a conduit 2l with one of the hydraulic transmitters 5l. Thus the hydraulic impulse of the transmitter serves to move the piston 69 against the tension oi a retracting spring 'H interposed between the piston and one end of cylinder 68. The speed change mechanism and the connections between it and arm lll-'ia are such that the piston movement opposed to spring 'H increases the speed transmitted through pinion lil and gear di to the cam drum. Movement of piston 69 in the reverse lby it discharge pipe Q2 direction by spring 7! correspondingly reduces the speed transmitted to the cam cylinder. To determine the maximum and minimum speeds which may be thus automatically provided by the hydraulic mechanism adjustable screws '12, 'i2 are mounted on bracket 'IS carried by the casing oi mechanism lll and serve to limit the swinging movement of lever fida.

By means of the described hydraulic devices for determining the speed of rotation of the cam drum 2s it is possible by the provision of a suitably shaped cam for actuating the transmitter connected to cylinder E8 to vary the speed of cam movement at will throughout the cycle oi rotation of the cam drum.

In Fig. 3 of the drawings is shown more or less diagrammaticaliy a machine element, hydraulic motor devices and pressure fluid supply means for the motor devices connected in a typical manner to the hydraulic transmitter control mechanism already described. The machine element f4 may be taken as a portion of the turret slide of thc turret lathe shown in 6 of the aforementioned earlier application, Serial No. I719,305. Associated with the slide is a hydraulic motor comprising a cylinder anchored at l5 and having a piston Ti with rod 'i8 connected by arm 'I9 to the slide element lil. rthis hydraulic motor is iitted with a hydraulically actuated control valve of the lollow type. The valve comprises a casing Se providing a chamber 30a for a spool valve Si and a chamber 8th for an actuating piston 32 having its rod 8S extending into chamber Stic to urge the valve 3! toward the right against the tension of spring 84. The chamber 8th is connected on the leit side of piston 32 with one of the conduits 2l leading to one of the hydraulic transmitters El. Piston rod 'E3 oi the main motor carries an arm to which is attached a follow rod 85 extending into chamber Stb. The latter chamber, on the right side of piston 62, is open to the atmosphere through vent so that no working iiuid for the main motor can leak past the packing oi rod 33 and affect the control piston.

A pump Bil of constant delivery type is directly driven by motor 3?: mounted upon the top of a sump chamber sii. The pump has its intake connected by a suction pipe Si with the interior of sump se and has a discharge pipe 92 with various branches to supply a plurality of hydraulic motors. One such branch 92a is shown connected to the inlet port oi valve casing 8G. The right end of the control valve chamber a discharges to a return pipe 93 delivering into sump 9d. Pipe 93 may also have branch return lines leading into it as indicated in Fig. 3.

To control the pressure of the working iluid delivered to the hydraulic motor or motors served is tted with a by-pass valve 9d of well known construction. To eiTect variation in the pressure of the working iluid supplied to the controlled motor or motors valve 94 is equipped with relief valve devices comprising casing 95, ball valve St and coil spring 91 which yieldingly urges the valve against the inlet port of casing 95, the outlet port being connected by conduit 98 to sump 90. To automatically vary the tension of spring 9'! casing 95 is provided with a chamber 99 for hydraulic piston IDU having a rod IBI engaging the end of spring 91. With chamber 99 connected as shown through a conduit 2| with one of the hydraulic transmitters 9 the impulse of the transmitter, determined by its actuating cam, serves to vary the tension of turns too fast.

7. spring 91 and hence the pressure at which the valve 96 opens to control the opening of by-pass valve 94. Casing structure 95 is -provided with a relief port |02 on the right side of piston |06.

i From what has been said it is apparent that the control apparatus is adapted automatically to control the amounts or distances of the powerdriven movements of one or more machine elements, to control the pressure of the Working liquid supplied to the motor or motors of the niachine elements during or in different parts of the movements of the said elements to thereby vary the force of the individual movements, to control the sequence in which the movements of the machine elements occur and also to control the speed with which the cycle or cycles of machine element movements, or parts of such cycles, are carried out.

Fig. 5 of the drawings shows how two of the motor-driven control units, designated Directer A and Director B can have their speed control cams coordinated to operate the directers at synchronous speeds, which may be either equal or different. This is accomplished by connecting the transmitter il of directer A through conduit 2l to the speed control cylinder Gt of the directer and the transmitter 9 of directer B through conn duit 2l to conduit 2l, so that both transmitters are connected to the same speed control cyl inder. The control arm Ma' of the variable speed mechanism 134 of directer B is looked by limit screws 12 in xed position for a relatively low speed. The adjusting screws 12 of transmitter 9 are positioned to permit a relatively small movement of arm 49a in a range corresponding to a higher speed than that of directer B. .The receiver piston 69 of directer A is required only to Vcorrect variations from synchronous speed and relatively small movement of arm 44a is sunlcient for this purpose. Accordingly the displacement incident to movement of piston 39 is small compared to the displacement of transmitters 9 and 9.

The speed control cams 33 and 33 of the two directors are formed so that directer A must make two revolutions for one of directer B. Therefore when the lever 64a' is set to speed, lever 44a must be set to twice that speed but with a limited range of movement to allow piston E9 to adjust for departure from synchronism.

As the cams revolve in the direction of arrow R follow arm 36 rises and transmitter 9' forces liquid into the common pilot conduit system. At the same time arm 36 falls and transmitter 9 withdraws an equal amount of liquid from the l system. Therefore no movement of piston E9 occurs. It will be observed that the rise on cam 33' between 0 and 10 equals the fall of cam 33 between and 2G. Suppose, now, that cam 33 Then transmitter 9 will remove (iff) oil faster than transmitter 9' supplies it and piston 69 will move lever 44a toward the left to a lower speed position, thereby correcting the overspeed. Conversely underspeed of directer A will move arm 44a to the right to bring the speed up to syn-chronism with directer B.

It is a peculiarity of the described system that the regulating action operates onlir when cam 33 is falling and cam 33' rising. Therefore there is a period of lost control while arm 36 rises and arm 36' falls. This period is made as short as possible as shown by lobe 33a of cam 33. Also advantage of this period is taken to refill 'the pilot system by providing filler notch H8. A'The departure from speed during this period is toward making directer A run too slow but the discre'p` ancy is limited by screw 12 on the low side of the control arm. Synchronous position and speed are quickly regained as soon as arm 36 is rising and arm 36 falling, so that the cycles of the two directers always end together.

In the foregoing disclosure the invention is applied to motor-driven control mechanisms but it will be apparent that the cam driven hydraulic interconnection of the synchronized motors can be applied to other kinds of motor driven units to effect their synchronization. Furthermore, it is to be understood that forms of construction varying, within the bounds of the following claim, from those herein disclosed can be used in thel practice of the invention.

What is claimed is:

In automatic apparatus, the combination of two mechanisms each comprising a motor drive device having means for varying its speed; manual means for adjusting and setting the speedvarying means of the rst mechanism to determine the speed of that mechanism; and automatic means for adjusting the speed-varying means of the second mechanism to determine the speed of the second mechanism in relation to the speed of the first mechanism, said automatic means comprising for each mechanism a hydraulic transmitter having a cylinder, a piston therein, and a rotary cam driven by the drive device of the mechanism for actuating the transmitter piston and comprising further -a hydraulic receiver cylinder, conduit means connecting both of the hydraulic transmitters to the inlet of the receiver cylinder and a piston in the receiver cylinder operatively connected to the speed-varying means of the second mechanism, the cam of the second mechanism having predominantly a falling slope while the cam slope of the first mechanism is predominantly rising to complement the slope of the other cam.

EDWARD M. MAY.

No references cited. 

